• many TraceCodeInjectors and TraceListeners supported in the same time via TraceExtension interface
• TraceExtensions could be provided via generic Service Provider Interface (SPI). It makes prod code independent on potential TraceExtension

• Coverage collection from many module's compilations
• Coverage report per line and instruction in HTML format

• add xquery-saxon-support to prod classpath and use SpiTraceExtensionProvider to obtain TraceExtension
• add xquery-saxon-coverage to test classpath and enable coverage collection via -Dxquery.saxon.coverage Java system property

Provide Java system properties

• -Dxquery.saxon.coverage - enables coverage collection
• -Dxquery.saxon.coverage.report.printing.on.shutdown - prints coverage reports on JVM shutdown in report directory
• -Dxquery.saxon.coverage.report.directory - report directory, default value is target/xquery-saxon-coverage